bridge mode without network rework

bridge mode without network rework

[Thomas Lau]

Hi All,

I just wondering is it possible not to rework our host machine network
structure to get KVM guest working on bridge mode? Current
implementation is using brctl to control it, which is destructive
especially you have a host which is using that network card to connect
internet.

Re: bridge mode without network rework

[Stefan Hajnoczi]

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On Mon, Dec 08, 2014 at 10:36:12AM +0800, Thomas Lau wrote:
> I just wondering is it possible not to rework our host machine network
> structure to get KVM guest working on bridge mode? Current
> implementation is using brctl to control it, which is destructive
> especially you have a host which is using that network card to connect
> internet.

Are you deploying KVM and worried about the one-time downtime that might
be introduced by setting up a bridged setup on the host?

Once you have the bridge working you can add/remove tap interfaces from
it without affecting the host's physical interface.

I'm not sure I understand the problem.

Perhaps macvtap is what you want:
http://virt.kernelnewbies.org/MacVTap
http://wiki.math.cmu.edu/iki/wiki/tips/20140303-kvm-macvtap.html

Stefan

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Re: bridge mode without network rework

[tlau]

Yes macvtap should be a solution, but somehow libvirt can't turn on VM itself afterwards. Any idea?

Sent from my BlackBerry 10 smartphone.

Thomas Lau
Director of Infrastructure
Tetrion Capital Limited
 
Direct: +852-3976-8903
Mobile: +852-9323-9670
Address: 20/F, IFC 1, Central district, Hong Kong
  Original Message  
From: Stefan Hajnoczi
Sent: Tuesday, 9 December, 2014 6:55 PM
To: Thomas Lau
Cc: kvm
Subject: Re: bridge mode without network rework

On Mon, Dec 08, 2014 at 10:36:12AM +0800, Thomas Lau wrote:
> I just wondering is it possible not to rework our host machine network
> structure to get KVM guest working on bridge mode? Current
> implementation is using brctl to control it, which is destructive
> especially you have a host which is using that network card to connect
> internet.

Are you deploying KVM and worried about the one-time downtime that might
be introduced by setting up a bridged setup on the host?

Once you have the bridge working you can add/remove tap interfaces from
it without affecting the host's physical interface.

I'm not sure I understand the problem.

Perhaps macvtap is what you want:
http://virt.kernelnewbies.org/MacVTap
http://wiki.math.cmu.edu/iki/wiki/tips/20140303-kvm-macvtap.html

Stefan

Re: bridge mode without network rework

[Stefan Hajnoczi]

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On Tue, Dec 09, 2014 at 07:21:40PM +0800, tlau@tetrioncapital.com wrote:
> Yes macvtap should be a solution, but somehow libvirt can't turn on VM itself afterwards. Any idea?

No, that sounds like a bug because libvirt supports macvtap.

Stefan

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Re: bridge mode without network rework

[tlau]

Since we decided not to go with KVM due to stability issue, we could let this go, thanks. 

Sent from my BlackBerry 10 smartphone.

Thomas Lau
Director of Infrastructure
Tetrion Capital Limited
 
Direct: +852-3976-8903
Mobile: +852-9323-9670
Address: 20/F, IFC 1, Central district, Hong Kong
  Original Message  
From: Stefan Hajnoczi
Sent: Friday, 19 December, 2014 6:56 PM
To: tlau@tetrioncapital.com
Cc: kvm
Subject: Re: bridge mode without network rework

On Tue, Dec 09, 2014 at 07:21:40PM +0800, tlau@tetrioncapital.com wrote:
> Yes macvtap should be a solution, but somehow libvirt can't turn on VM itself afterwards. Any idea?

No, that sounds like a bug because libvirt supports macvtap.

Stefan

Re: bridge mode without network rework

[Paolo Bonzini]

On 19/12/2014 11:59, tlau@tetrioncapital.com wrote:
> Since we decided not to go with KVM due to stability issue, we could let this go, thanks. 

That's a pity.  That said, your decision to not go with KVM due to
stability is a bit strange:

1) unless you are using open source Xen, you are presumably going for a
commercial solution that would cost you money anyway.  Have you thought
of asking for commercial support, either from Canonical (since you were
using Ubuntu) or from anyone else?

2) I saw now that you were using 3.13.  I'm sorry for not having noticed
that early, but have you tried upgrading the kernel?  There is a known
bug with Ivy Bridge EP and hv_vapic, but it's fixed on newer kernels
(3.16).  If you are not going to pay anyone for support, you probably
should have thought about this yourself.  If you hadn't thought about
it, and you are going for an open source solution (which I hope), you
probably should re-evaluate the plan of not paying anyone for support,
either a company or someone with enough expertise.

Paolo

Re: bridge mode without network rework

[Zhang Haoyu]

On 2014-12-20 02:07:27, Paolo Bonzini wrote:
> 
> On 19/12/2014 11:59, tlau@tetrioncapital.com wrote:
> > Since we decided not to go with KVM due to stability issue, we could let this go, thanks. 
> 
> That's a pity.  That said, your decision to not go with KVM due to
> stability is a bit strange:
> 
> 1) unless you are using open source Xen, you are presumably going for a
> commercial solution that would cost you money anyway.  Have you thought
> of asking for commercial support, either from Canonical (since you were
> using Ubuntu) or from anyone else?
> 
> 2) I saw now that you were using 3.13.  I'm sorry for not having noticed
> that early, but have you tried upgrading the kernel?  There is a known
> bug with Ivy Bridge EP and hv_vapic, but it's fixed on newer kernels
> (3.16).  If you are not going to pay anyone for support, you probably
Hi, Paolo,
do you mean the commit fc57ac2 KVM: lapic: sync highest ISR to hardware apic on EOI ?
I want to backport it to our product.

Thanks,
Zhang Haoyu

> should have thought about this yourself.  If you hadn't thought about
> it, and you are going for an open source solution (which I hope), you
> probably should re-evaluate the plan of not paying anyone for support,
> either a company or someone with enough expertise.
> 
> Paolo

Re: bridge mode without network rework

[Paolo Bonzini]

On 24/12/2014 02:02, Zhang Haoyu wrote:
> Hi, Paolo,
> do you mean the commit fc57ac2 KVM: lapic: sync highest ISR to hardware apic on EOI ?
> I want to backport it to our product.

Yes.

Paolo